Electron tube marking



1953 J. WEINGARTEN ELECTRON TUBE MARKING 2 Sheets-Sheet 1 Filed Sept.10. 1948 FIG.|

22 l3 8 I 7 I 1\ l! x h I DEFLECTION 43/ PQWER SIGNAL SUPPLY SOURCE FIG.4

' INVENTOR JOSEPH WEINGARTEN ATTORNEY Oct. 27, 1953 Filed Sept. 10, 19482 Sheets-Sheet 2 INVENTOR JOSEPH WEINGARTEN ATTORNEY Patented Oct. 27,1953 UNITED STATES PATENT OFFICE 18 Claims. (Cl. 95-5) (Granted underTitle 35, U. S. Code (1952),

sec. 266) This invention relates in general to the electron tube artand, more particularly, concerns the utilization of photographicapparatus and techniques for individually processing characteristicmarkings upon cathode ray and similar electron tubes. The presentapplication is a continuation-in-part of the application of JosephWeingarten, Serial No. 669,557, filed May 14, 1946, for Cathode Ray TubeCalibration, which matured into Patent 2,449,093 on September 14, 1948.

Cathode ray tubes and similar electron tubes are widely used inelectrical apparatus for the observation, recording and measurement ofelectrical signals. Cathode ray tube applications ex tend intosubstantially all phases of the electronic art, as in radar, television,facsimile, and the like.

Briefly, the conventional cathode ray tube comprises an electrodestructure, known as an electron gun, for generating an electron beamwithin a glass or other suitable envelope. The electron beam is normallyfocussed to a sharply defined point upon a fluorescent screen in theface of the tube, thereby providing a luminous spot. Deflection means inthe form of orthogonal electrodes (electrostatic) or coils(electromagnetic) permit displacement of the spot in a predeterminedpattern for forming a visible trace upon the screen.

In numerous well-known devices, cathode ray tubes are used solely forqualitative analysis, for

aid in determining maxima and minima, or for image reproduction, andconsequently do not require calibration, reference lines, or othersubstantially fixed visible markings. On the other hand, cathode raytubes are in extensive use in analytical apparatus, as in oscillographs,spectrum analyzers, radar systems and television test equipment; whereinprecise measurements of the trace appearing upon the screen areessential. Markings related to predetermined movement of electrons mustbe provided for the latter applications.

of the cathode ray tube screen. In radar appli-' cation, a transparentmap is often placed before a cathode ray tube plan position indicator sothat the relationship of target echoes to the surround ing terrain maybe observed visually. lhe application of a transparent map is ofparticular importance where moving target radar indication is employed,since only echoes of objects in motion appear while radar echoes of thestationary terrain are entirely suppressed.

It is generally known that the deflection sensitivity of a cathode raytube, defined as the displacement of the fluorescent spot obtained for aunit change of deflection potential or current, is a marked function ofthe position of the spot upon the screen. Therefore, the aforementionedcoordinate scale systems are seriously handicapped by the fact that thedistance between adjacent coordinate lines at one point on the tubescreen is not representative of a deflection signal magnitude which willcause equal displacement at another point on the screen surface.Calibration of a printed scale must thus be accomplished experimentally,and involves the accumulation of considerable data, which data must beavailable before cathode ray tube images may be successfullyinterpreted. Prior cathode ray tube coordinate scales, printed maps, ortest patterns have the further disadvantage of failing to take intoaccount faults in tube construction, such as non-orthogonality of thedeflection means. Also, these scales do not account for inherentstructural variations from tube to tube, and permit errors due toparallax, since such printed indicators are fiat while tube screens aregenerally warped surfaces. For these reasons, laboratory personnelconsistently avoid the use of large deflections and perform measurementsin the central region of the tube face whenever possible.

The aforementioned patent fully discloses a cathode ray tube screenmarking which successfully permits utilization of substantially theentire visible surface of the tube screen for precise measurement. Asdescribed therein, a scale marking individual to the cathode ray tubewas photographically obtained by first applying a light sensitivesubstance, in the form of a coating, over the face of the tube inproximate relation with the fluorescent screen. Operating potentialswere then applied, producing a sharply defined spot which was deflectedand varied in intensity to trace out a predetermined coordinate system,exposing the light sensitive coating through the glass separationbetween coating and fluorescent screen. Thereafter, conventionalphotographic processing of the exposed coating provided substantiallypermanent coordinate scale markings.

In marking cathode ray tubes in accordance with the procedures outlinedin the aforementioned patent, certain problems may be encountered,particularly where the separation between fluorescent screen and lightsensitive coating is sumciently large to cause excessive diffusion oflight passing therethrough. Where the developed image of the cathode raytube luminous trace is blurred somewhat by passage through a thick glasswall, it is still possible to obtain accurate marking by inking thecenter of such trace. This, however, is a, tedious process not too welladapted to mass production techniques.

The present invention contemplates and has as a primary object theprovision of novel means and procedures for providing individualelectron tube markings. In accordance with the principles of thisinvention, a cathode ray or like electron tube is individually marked byexposing a light sensitized surface thereof to a recorded image of thedesired markings, this image bearing a predetermined relationship to themovement of electrons within the tube.

In one form of the invention, a cathode ray tube is supported in fixed,spaced relation with a camera and a predetermined deflection andintensity pattern of theluminous spot is photographed thereby. The faceof the cathod ray 3 tube is then sensitized, and an image of theluminous spot deflection pattern, as photographically recorded, isprojected or otherwise impinged upon th sensitized surface in preciseregistration with the original luminous pattern 1 is to provide meansfor individually marking cathode ray tubes of all sizes with sharplydefined lines related to the movement of the oathode ray tube trace.

These and other objects of the present inven tion will now becomeapparent from the following detailed specification when taken inconnection with the accompanying drawings in which:

Fig. l is a general view of apparatus utilized for photographing acathode ray tube luminous trace;

Fig. 2 is a view of a representativ negative.

obtainable with the apparatus of Fig. 1;

Fig. 3 illustrates the appearance of the negative in Fig. 2 followingreversal;

Fig. 4 is a perspective view, partly in section, illustrating a step inth process of cathode ray tube marking as disclosed herein;

Fig. 5 is a general View of the apparatus of Fig. 1, modified for thepurpose of impinging an image upon a cathode ray tube;

Fig. 6 is a general perspective view of a calibrated cathode ray tube;

Fig. '7 is a fragmentary perspective view, partly in section,illustrating the structural details of the face of the cathoderay tubeof Fig. 6; and

Fig. 8 is a fragmentary perspective view of a cathode ray tube such asis shown in Fig. 6, but with markings thereon for special radarapplication.

With reference now to the drawings, and more particularly to Fig. 1thereof, there is illustrated apparatus for forming and photographicallyrecording an image appearing upon the face of a cathode ray tube l l ofthe electrostatic deflection type. Basically, this apparatus comprises along, cast metal frame 12, similar to the bed of a lathe or like machinetool, formed with a longitudinal slot (not shown) and adapted to supportoppositely disposed, longitudinally slidable standards (3 and [4.

Standard l3 comprises a metal casting having integrally formed basemembers l5 and [6 which, subsequent to longitudinal adjustment along bed(2, may be releasably secured by clamps IT and 18, respectively.Extending upward from stand ard i3 are integral supports 21 and 22 towhich a metallic cathode ray tube shield and support 23 is rigidlyfastened.

As shown, metallic shield 23 comprises a substantially conical sectionextending and flaring outwardly from an integral cylindrical section.Shield 23 thereby conforms to the outline of cathode ray tube ii. Theleft-hand end of supporting shield 23, as viewed in Fig. 1, is sealed bya securely attached cylindrical cap 24 which, in turn, encloses asuitable cathode ray tube connecting socket Thephysical relationship ofconnecting socket '25 and supporting shield 23 is fixed a plurality ofscrews 26 extending into socket 25 through cap 24. Electrical connectionto cathode ray tube H is made through a connector 27 and a flexiblecable 3| extending therefrom through cap 24 into socket 25; the latterelement engaging the connecting pins extending from tube base 33.

In the conventional manner, the base 33 of cathode ray tube ii andsocket 25 are formed with mating key and keyway, respectively (notshown). The position of cathode ray tube H with respect to frame [2 isconsequently uniquely determined, and will not be changed by repeatedinsertion and withdrawal. For a cathode ray tube which does not utilizea key for fixing the relative position of insertion in a connectingsocket, other suitable position determining apparatus may, of course, beprovided.

The electrode system for generating and deflecting an electron beamwithin tube l I has been schematically illustrated, and comprises anindirectly heated cathode 34, followed axially by an intensity controlgrid 35, focussing and accelerating electrodes 38 and 31, respectively,and orthogonal (horizontal and vertical) deflection plates 33. Forreasons of clarity, electrical wiring to these electrodes has been shownin Fig. l as extending directly through the wall of the tube. Anelectromagnetic deflection type tube is in most respects structurallysimilar; however, or hogonal deflection plates 38 are replaced byorthogonal deflection coils affixed externally of the tube. Supportingshield 23, which also functions to preclude interference by strayfields, may be readily modified for application of this invention toelectromagnetically deflected cathode ray tubes.

The inner face of cathode ray tube H is uniformly covered with afluorescent phosphor 4| generating a luminous spot upon the impact ofthe tube electron beam, schematically represented by. broken line;

Deflection. of the electron beam and simultaneous control of theintensity thereof produce the desired image upon the phosphor.

For marking the face of cathode ray tube ll, connection is made to anenergizing circuit which, in general, comprises a power source forapplying normal operating potentials to the tube and means for sweepingthe beam in a predetermined intensity and delection pattern. In Fig. l,a calibrating circuit for cathode ray tube II has been shown in blockform as a power source 43 for the electrodes of the tube electron gun,and a deflection signal source 44 for energizing deflection plates 38.Deflection signal source 44 is coupled to power supply 43 for purposesof obtaining suitable operating potentials therefor.

To provide cathode ray tube II with an individual orthogonal coordinatesystem, power supply 43 and deflection signal source 44 may be arrangedand connected to the tube electrodes in the manner fully disclosed inthe aforementioned patent. Such arrangement results in deflection ofelectron beam 42 to form a uniform, luminous, linear trace, anddeflection of this trace in equipotential steps in mutuallyperpendicular directions. Throughout the deflection period, the electronbeam intensity is controlled by application of suitable blankingsignalsto control grid 35. Inasmuch as the details of the cathode ray tubeenergizing circuit are not critical to an understanding of the presentdisclosure, further discussion thereof is deemed unessential at thispoint.

standard l4 supports, as illustrated in Fig. 1, means for photographingthe luminous pattern presented upon fluorescent screen 4| of cathode raytube H. Basically, standard l4 comprises a base member 45 adapted forlongitudinal motion along frame l2 and a clamp 41 for releasably lockingthis member. Afiixed to the upper portion of standard I4 is aconventional mechanical feed which includes a table and a feed screw 5|disposed axially of the bed l2, and driven by adjusting hand wheel 52.This feed screw engages slide 53 and thus, rotation of hand wheel 52results in axial movement of slide 53.

A camera 54 is positioned upon slid 53 and arranged whereby the opticalaxis thereof coincides precisely with the longitudinal axis of cathoderay tube obtain fine adjustment of the axial spacing between the screen4l of cathode ray tube II and the focal plane of camera 54.

In practical application of this invention, it is preferable that camera54 be of the 35 mm. or 70 mm. type adapted to permit a considerablenumber of exposures for each film loading. In order to minimizedistortion and thereby increase the accuracy of the markings providedfor cathode ray tube H, bed I2 should be of sufficient length to permitthe utilization of a comparatively long focus lens for camera 54. Inthis manner the angle a subtended by fluorescent screen 4| of cathoderay tube H, is maintained at a desirable small value.

To mark the face of cathode ray tube II with the apparatus illustratedin Fig. 1, the tube is inserted into supporting shield 23. The axialspacing between fluorescent screen 4| and the focal plane of the camera54 is then set by adjustment of the spacing of standards l3 and I4. Fineadjustment of this separation may be made by handwheel 52.

Camera 54 is then focussed upon fluorescent screen 4| through the glassenvelope of cathode Hand wheel 52 is employed to ray tube At this point,cathode ray tube H is energized from power supply 43 and deflectionsignal source 44 so that its electron beam will sweep out a luminouspattern of the desired form upon fluorescent screen 4|. The entireapparatus is operated in a dark room so that camera 54 only records theluminous pattern.

The nature of the exposure required by the film in camera 54 will bedependent upon the nature of the particular luminous configuration beingphotographed. Thus, if substantially automatic calibration means areemployed to sweep the electron beam in the manner described in theaforementioned patent application, the camera shutter may be set forTime and the entire pattern recorded during a single exposure. Asdescribed in the aforementioned patent, the electron beam may be blankedduring periods of trace movement, and accordingly, only distinct lineswill be photographed. Blanking means, however, need not be employed torender the trace invisible during periods of motion between fixed,visible steps thereof, since the shutter of camera 54 may be closedwhile the trace is being properly positioned upon the fluorescent screenand opened thereafter for the time required to expose the film.Operation of the camera shutter and the deflection signal source 44 maybe readily synchronized electrically or mechanically.

A large number of tubes may be photographed in sequence upon one stripof film. It is, of course, essential that each exposure on the filmstrip be identified in relation to the cathode ray tube screenphotographed.

Subsequent to exposure, the film is removed from camera 54 anddeveloped. With reference now to Fig. 2 there is illustrated a developedfilm section 5| containing an exposure representative of a rectangularcoordinate calibration of a typical cathode ray tube. The generallycircular image 62 is an orthogonal grid of alternate heavy and lightblack lines upon a clear background. Each line of image 52 is thephotographic reproduction of a linear trace of cathode ray tube H. Forthe image illustrated, the coordinate lines are separated by spacesrepresenting the deflection caused by a predetermined change ofdeflection potential. Alternate light and dark lines are obtained, inaccordance with the principle disclosed in the aforementioned patent, ofcorrespondingly varying the trace intensity as it is displaced acrossthe face of the tube.

For reasons which will become apparent upon further consideration ofthis disclosure, the image on film section is then reversed. Reversalmay be accomplished directly during the development of film section (5|or by contact printing upon another film section subsequent todevelopment. Film section 6i, as reversed, is illustrated in Fig. 3; andthe reversed image 63 comprises a grid of white lines upon a dark field.

After the luminous pattern appearing on screen 4| has been photographed,a described above, cathode ray tube is removed from the apparatus ofFig. l, and the outer face thereof filmed with an adhering lightsensitive substance, preferably in the form of a silver halide emulsionas used for photographic plates. The filming process is comparativelysimple and may be accomplished on a reduced scale in the mannerillustrated in Fig. i. In this figure, cathode ray tube H is shownpartially immersed in liquid sensitive emulsion B4 within vessel 55. The

accuse:

depth of immersion need only be sufficient to coat the outer surface oftheglass face 15 to .the

circular bounding edge of the fluorescent screen 4| (Fig. 1).

prior to immersion in the light sensitive substance B l. To eliminateair bubbles-and to obtain a uniform film, the tube l l is rotatedduringimmersion as shown in Fig. 4.

carried out under lighting conditionsconsistent with the nature of thesensitive materialv 64..

Preferably, the applied emulsion is of high contrast, non-panchromatictype so-thatiit may be.

as recorded in photographic film 6|, upon the sensitizes. face ofcathode ray tube H in precise register with the original luminouspattern formed upon fluorescent screen-4i. Essentially, the apparatusillustrated in Fig. 5 is that described in connection with" Fig. l forexposing film 6i, with the exception that no circuit connections aremade to cathode ray tube- H and that camera 55 is replaced by projector=51. Thus, cathode ray tube ll, filmed as described in connection withFig. 4, is inserted within the conductive shield 23 so that itsconnecting pins are engaged within socket 25 (not shown in Fig. 5). Thekey and lreyway arrangement described above, insure'that the relativeposition of cathode ray tube ll, when set for image projection as inFig. 5, is precisely the same as when inserted for photographing in Fig.1.

Projector Si is supported upon standard [4 so that its optical axis iscoincident with the longi-- tudinal axis of cathode ray tube ll.Preferably, lens focal lengths and lens to tube distances are equal inFigs. 1 and 5. Accordingly, the angle a subended by the face of cathoderay tube H in 5 equals that shown in Fig. 1.

Film section bearing the reversed image 63 illustrated in Pi". 3, isinserted into a negative carrier ll hich properly positions the filmduring projection. The projected image-l2 is sharply focussed so thatdistinct lines are obtained upon the filmed tube screen, and theselines, because of the reciprocal arrangement of camera and projector(Figs. 1 and 5), are in exact registration with the original luminouslines photographed. Luminous registration mark rs (not shown) extendingradially from shield 23 may be employed to simplify the registrationproblem.

Subsequent to exposure in the apparatus-of Fig. 5, the sensitized outersurface of the cathode ray tube 1 l is processed. The processingrequired is a function of the type of coating material utilized. For theconventional photographic emulsion, processing includes the steps ofdevelopment, rinsing and fixing. This may be carried out in a mannersimilar to that disclosed in connection with l, except that liquidemulsion Ed is successively replaced by the required developer, rinseand fixer. It is preferable that development be carried out for' a"comparatively A transparent base coat, such-as collodion, may of coursebe appliedtozthe glass It is, of course. evident that the operationdepicted in Fig. 4.is

When dry, the-face of the.

short time-in ahigh contrast'developer toprovide a distinct marking.Fixing of the sensitive film is followed by a final rinse and drying. Atthis point the cathode ray tube is complete with fixed, individualmarkings of a coordinate system conforming to the surface of the glassface of the tube. The processed photographic emulsion may be protectedbya suitable coating of varnish, or the like.

In Fig. 6, cathode ray tube H is illustrated completewith calibrated andprocessed film 13. Since the reversedimage 63 (Fig. 3) was projected,the scale comprises a grid of black lines upon a transparent field. Fig.7, which i a fragmentary perspective view of cathode ray tube l l,illustrates in section, the'composite tube face structure; namely,fluorescent screendl, glass envelope (5,: and the adhering processedphoto-- graphic coating, "F3.

The rectangular coordinate; system of lines.

shown upon the face of cathode ray tube H in Figs. 6 and '7 providesaccurate means for studying signal waveforms. It is emphasized that dueto the variation of the deflection sensitivity over the screen surface,the physical spacing between lines of coordinate system will notnecessarily be uniform. However, the space between two adjacent lines istruly representative of a predetermined deflection potential and is-inde pendent of the variable physical spacing therebetween.

This result is obtained because the space between lines represents afixed deflection potential. A tube marked by means of the apparatusillustrated in Figs; 1 and 5 is literally custom calibrated. Parallaxerrors are reduced substantially'as a result of theuniform proximaterelation between the processed photographic layer 13 and the fluorescentscreen M.

The broad principle hereinabove disclosed may be utilized as a basis forobtaining a cathode ray tube marking of any desired form. Thus, thedeflection signal source 44 illustrated in Fig. 1 may beemployed toprovide for a luminous tracedefiection and intensity patterncorresponding to signals typical of those observed upon the oath--Ode-ray tube in its ultimate application.

Fig. 8 is a fragmentary view of a cathode ray tube ll of the type whichmay be employed in a radar plan position indicator. A map 72 of thesurrounding terrain and circular range markers, as actually recorded bythe tube ll when in radar use, is shown over the tube face. hasbeen-prepared in accordance with the steps outlined above for applying acoordinate scale. For radar purposes, the density is controlled so thatthe developed image illustrated in Fig. 8 contains no deep blacks, andthus, target echoes appearing upon the fluorescent screen while inactual operation will at all points be visible through-the photographicreproduction. When the plan position indicator type cathode ray tubeshown in Fig. 8 is employed for moving target indication; only targetsin motion will appear upon the face or" the tube and these will bepresented in relation to the terrain marked upon the face of the tube.

For television test purposes, the cathode ray tube may bephotographically marked in accordance with a test patern. This patternmay be generated and photographed in the apparatus illustrated in Fig.l, and projected upon the oathode ray tube in the apparatus illustratedin Fig. 5;

It is thus apparent that' numerous modifica- The map 13 l tions andextensions of the principles herein disclosed may become evident tothose skilled in the art. Accordingly, it is preferred that the scope ofthis invention be limited solely by the spirit of the appended claims.

The invention disclosed herein may be manufactured and used by or forthe Government of the United States of America for Governmental purposeswithout the payment of any royalty thereon or therefor.

What is claimed is:

1. The method of applying predetermined markings to a cathode ray tubewhich comprises the steps of presenting a luminous image upon said tube,preparing a substantially permanent photographic record of said imageapart from said cathode ray tube and photographically processing areproduction of at least a portion of said separate photographic recordupon said tube.

2. The method of applying predetermined markings to a cathode ray tubewhich comprises the steps of energizing said cathode ray tube to presenta luminous image having the configuration of the aforesaid markings,preparing a photographic record of said luminous image, applying asensitive substance to said cathode ray tube and photographicallyprocessing a reproduction of said photographic record into saidsensitive substance.

.3. The method of applying predetermined markings to a cathode ray tubewhich comprises the steps of energizing said cathode ray tube to presenta luminous image having the configuration of the aforesaid 'markings,preparing a photographic record of said luminous image, applying asensitive substance to said cathode ray tube and photographicallyprocessing a reproduction of said photographic record into saidsensitive substance in register effectively with said luminous image.

4. The method of marking a cathode ray tube having a fluorescent screen,which comprises the steps of energizing said cathode ray tube to presenta predetermined luminous pattern upon said screen, preparing aphotographic record of said luminous pattern, applying a sensitivecoating to said cathode ray tube in proximate relation with saidfluorescent screen and impinging a luminous image of said photographicrecord of said pattern upon said coating in register effectively withthe position of the aforesaid luminous pattern upon said fluorescentscreen.

5. The method of marking a cathode ray tube having a fluorescent screen,which comprises the steps of energizing said cathode ray tube to presenta predetermined luminous pattern upon said screen, preparing aphotographic record of said luminous pattern, applying a sensitivecoating to said cathode ray tube in proximate relation with saidfluorescent screen, impinging a luminous image of said photographicrecord of said pattern upon said coating in register effectively withthe position of the aforesaid luminous pattern upon said fluorescentscreen, and processing said sensitive coating to provide substantiallypermanent markings in proximate relation with said fluorescent screen.

6. The method of marking a cathode ray tube having a fluorescent screenand means adapted to produce a luminous spot thereon, which comprisesthe steps of energizing said cathode ray tube and sweeping said luminousspot in a predetermined deflection and intensity pattern, preparing aphotograph of at ieast a portion of said spot deflection and intensitypattern, applying a light sensitive substance to said cathode ray tubein proximate relation with said fluorescent screen, projecting aluminous image of said pat tern from said photograph upon said sensitivesubstance, the relative position of said luminous image upon saidsubstance during projection overlying and corresponding with theposition 00- cupied by said pattern upon said fluorescent screen, anddeveloping and fixing said sensitive substance.

'7. The method of substantially permanently marking the face of acathode ray tube having a fluorescent screen, which comprises the stepsof energizing said cathode ray tube with substantially normal operatingpotentials to provide a luminous spot on said fluorescent screen,exposing a film within a camera to light from said spot, deflecting saidluminous spot, developing said film to provide an image of the patterntraced by said spot on said fluorescent screen, applying a lightsensitive photographic emulsion to said face of said cathode ray tube inproximate relation with said fluorescent screen, projecting a luminousimage of said developed film upon said sensitive emulsion in registereffectively with the luminous image upon said fluorescent screeninitially photographed with said camera, thereby exposing said emulsion,and developing and fixing said exposed emulsion to provide markingsadjacent to said fluorescent screen and bearing a relation to thedeflection of the luminous spot of said cathode ray tube. r

8. The method of claim 7, and including the step of photographicallyreversing said developed film prior to projection upon said sensitiveemulsion, whereby the markings corresponding to the movement of saidspot as developed in said exposed sensitive emulsion are dark upon asubstantially transparent field.

9. The method of marking the face of a cathode ray tube having a.fluorescent screen, which comprises the steps of applying a sensitivesubstance to said tube adjacent to said screen and impinging a luminousimage upon said substance from without said tube.

10. The method of applying predetermined markings to a cathode ray tubehaving a fluorescent screen which comprises the steps of preparing aphotographic film having an image of said markings, covering said tubeadjacent said screen With a sensitive substance, projecting said filmimage upon said sensitive substance and processing said sensitivesubstance.

11. The method of applying markings to a cathode ray tube bearing arelation to luminous images on said tube during normal operationthereof, which comprises the steps of normally energizing said cathoderay tube to present a luminous image, photographing said luminous imageto provide a record thereof and processing record of said image uponsaid cathode ray tube in predetermined relation to the position of saidluminous image when photographed.

12. The method of marking a rectangular coordinate system of lines uponthe face of a cathode ray tube, which comprises the steps of energizingsaid cathode ray tube with substantially normal operating potentials toprovide a luminous spot on said tube face, sweeping said spot in a firstdirection while deflecting said spot in distinct steps in a seconddirection perpendicular to said first direction, sweeping said spot insaid second direction while deflecting said spot in distinct steps insaid first direction, blanking said spot during each of said distinctdeflecting steps,

thereby presenting a grid of luminous lines upon saidtube face, exposinga film within-a camera to said grid of lines, processing said'fllm,applying a light sensitive emulsion to the face of said cathode raytube, projecting a focussed luminous image of said film upon saidemulsion to expose said emulsion and developing and fixing -saidsensitive emulsion.

13. Apparatus for marking a cathode ray tube comprising, means forenergizing said cathode raytube to display an image to berecorded, meansfor photographing said cathode ray tube, means for securely supportingsaid cathode ray tube and said photographing means in predeterminedspaced relationship, an image projector, said lastmentioned means beingarranged to support said cathode ray tube and said image projectorinsaid predetermined spaced relationship.

14. The method of applying predetermined markings to the face of acathode ray tube having a fluorescent screen, which comprises the stepsof preparinga record of said markings, sensitizing said cathode ray tubeina region in proximate relation with said fluorescent screen, impinginga luminous image of said markings from said record upon the region sosensitized from Without said cathode ray tube and processing saidsensitized region.

15. The method of applying predetermined markings to the face of acathode ray tube having a fluorescent screen, which comprises the stepsof preparing a substantially permanent photographic record of saidmarkings, photographically sensitizing the face of said cathode ray tubein a region in proximate relation with said fluorescent screen, exposingthe region so sensitized to a luminous image of said photographicrecord, and photographically processing said sensitized region.

16. The method of-applyingto-theface of a cathode ray tube markingsbearing apredetermined relation-to images presentablegon said tubeduring normal operation thereof which comprises the steps of preparing arecord of said markings, applying a sensitive substance tosaid tube,impinging from without said'cathode ray tube and from said record animage of said markings upon said sensitive substance, and processingsaid sensitive substance.

17. Apparatus for marking a'cathode raytube comprising astructuralframework. means upon said framework for releasably and. nonrotatablysupporting a. cathode ray tube inapredetermined position, means forphotographingsaidcathode ray tube, means upon said framework forsupporting said photographing means on the longitudinal axis of saidcathode ray tube, an image projector, said last-mentioned means beingarranged to support said image projector on said axis for projectionupon said cathode ray-tube. of an image recorded by said photographingmeans. 18. Apparatus for processing markings upon the face of acathoderay tube in proximate, relation with the fluorescent screen thereofcomprising, av structural framework. an, electrical connection socketsecured to said framework for receiving said cathode ray tube, means forfixing the relative positionv of said cathode. ray tube with respect tosaid framework, a camera, an image projector, means on said frameworkfor alternatively supporting. said camera and said image projector.onrthe longitudinalaxis of said cathode ray tube in spaced'relationshiptherewith.

JOSEPH WEINGARTEN.

References Cited in the, file of this patent UNITED STATES PATENTSNumber Name Date 1,818,760 Selenyi Aug. 11, 1931 2,152,487 Knoll Mar.28, 1939 2,176,225 Ogloblinsky Oct. 1'7, 1939 2,186,268 Pakala Jan. 9,1940 2,195,444 Brett Apr. 2, 1940 2,241,809 De Forest May 13, 19412,251,984 Cleaver et a1 Aug. 12, 1941 2,292,045 Burnett Aug. 4, 19422,294,015 Salb et a1 Aug. 25, 1942 2,330,604 Messner, Sept. 28, 19432,428,427 Loughren Oct. 7, 1947 2,446,674 Sproul..- Aug. 10, 19482,449,093 Weingarten. a--- Sept. 14,1948 2,449,752. Ross Sept. 21, 19482,457,744 Sturm "1 Dec. 28, 1948 2,462,263 Haynes Feb. 22, 19492,483,147 Mol. Sept. 27,1949

FOREIGN PATENTS Number Country Date 591,856 Great Britain Sept. 1, 1947

1. THE METHOD OF APPLYING PREDETERMINED MARKINGS TO A CATHODE RAY TUBEWHICH COMPRISES THE STEPS OF PRESENTING A LUMINOUS IMAGE UPON SAID TUBE,PREPARING A SUBSTANTIALLY PERMANENT PHOTOGRAPHIC RECORD OF SAID IMAGEAPART FROM SAID CATHODE RAY TUBE AND PHOTOGRAPHICALLY PROCESSING AREPRODUCTION OF AT LEAST A PORTION OF SAID SEPARATE PHOTOGRAPHIC RECORDUPON SAID TUBE.